It is known to use isostatic pressure techniques to diffusion bond metal components together. Diffusion bonding occurs when two mating surfaces are pressed together under temperature, time and pressure conditions that allow interchange of atoms across the interface. It is necessary that the surfaces to be joined are clean and that the variables of temperature, pressure and time are closely controlled, so that the necessary interchange of atoms may be achieved. Isostatic pressing is the application of high pressure gas (e.g. argon) at high temperature within a pressure vessel to the components to be joined. Gas pressure is applied isostatically so that there are minimal or no changes to the geometry of the components being joined. This diffusion bonding process requires the efficient sealing of the components, and conventionally, this has been accomplished outside the pressure vessel in a preliminary step. However, the seal between the components after this preliminary step is fragile, and great care has to be taken in moving the joined components to the apparatus where the diffusion bonding process is to be carried out.
Further, as it relates to parts for the impact protection of jet engine fan blades, such parts are exposed to potential impacts from birds and other foreign objects specifically during takeoff where the parts are under the most severe stress while at the same time being the most susceptible to impacts. Conventionally, the parts were constructed as one-piece. However, the one-piece part is costly to manufacture. Two-piece parts having a welded joint and/or a bonded joint via a conventional diffusion bonding process could not withstand the impacts associated with the use of the parts. The raw material required to make a one-piece part is costly and is double the cost of a two-piece part. This along with the amount of machining required to generate the internal and external surfaces is tremendous. Most of the machining time required is to produce the internal surfaces and specifically an internal nose radii due to the depth of cut and the small size of the internal nose radii and therefore the need to use small cutting tools.
The present disclosure provides a process of diffusion bonding which overcomes certain difficulties with the prior art methods while providing better and more advantageous overall results.